Please help... Why do you think it was so important to science when Alfie Wegener and Harry Hess has proved their theories of continental drift and seafloor spreading

Alfred Wegener produced evidence in 1912 that the continents are in motion, but because he could not explain what forces could move them, geologists rejected his ideas. Almost 50 years later Harry Hess confirmed Wegener's ideas by using the evidence of seafloor spreading to explain what moved continents.